1. Field of the Invention
The invention relates to an apparatus for removing injection molded articles from the opened injection mold of injection molding machines.
2. Description of the Prior Art
An apparatus of this type includes a grasping member for grasping the injection molded articles. After the mold halves of the injection mold in the closing unit of the injection molding machine have been moved apart, the grasping member is lowered to enable grasping of the molded articles and, after the molded article has been grasped, it is again moved upwardly out of the range of the closing unit. If a high productivity is to be achieved, these movements of the grasping member must be at a high speed. In apparatus of the aforementioned type, the grasping member is attached to a support member which, in turn, is supported by a carriage which moves along a guide member extending in the closing direction of the injection mold. This carriage must also reach high travel speeds, so that the molded articles removed from the injection mold can be dropped off outside of the working range of the injecting molding machine.
In order to obtain high travel speeds of the support member and the carriage carrying the support member, pneumatic linear drives are utilized in the apparatus for removing injection molded articles. The drives include pistons to which compressed air is admitted on two sides.
The pneumatic linear drives of a known type have the disadvantage that when the piston is moved into the desired position, the air present above or below the piston in the working chambers acts as a spring on the piston, so that the piston and the structural part moved by the piston are oscillated in an uncontrolled manner before reaching the desired position of rest.
The oscillation described above of the piston and the structural part connected to the piston is particularly disadvantageous with respect to the grasping member for the molded articles which is moved into the closing units or between the moved-apart mold halves of the injection mold, because the grasping member can only grasp the molded article properly when the grasping member has come completely to rest in the desired position. Thus, the movement of the support member and the grasping member supported by the support member must be adjusted in such a way that the oscillations have ended at the moment the grasping member grasps the molded article in the opened injection mold.
It is, therefore, the primary object of the invention to avoid the aforementioned disadvantages of the known apparatus. Particularly, it is the object of the invention to improve an apparatus of the known type for removing molded articles from the opened injection mold of an injection molding machine, so that an oscillation of the grasping member for the molded article is effectively prevented at least in the removing position of the grasping member in which it is moved into the opened injection mold.